Magnetic drafting mechanism



March 5, 1963 v. A. BURNHAM 3,079,646

MAGNETIC DRAFTING MECHANISM Filed July 20, 1959 3 Sheets-Sheet 2 March 5, 1963 v. A. BURNHAM MAGNETIC DRAFTING MECHANISM 3 Sheets-Sheet 3 Filed July 20. 1959 ilfaiteci erases Fatent G 3,079,646 MAGNETHI DRAFTENG MECHANKSM Virgil A. Burnham, Saco, Maine, assignor to Saw-Lowell Shops, Boston, Mass, a corporation of Maine Filed July 29, 1959, Ser. No. 823,247 5 Claims. (Cl. 19-272) This invention relates to drafting devices of the type used in textile machines, such as spinning and roving frames and the like, wherein pressure must be applied by the drafting devices to the fibrous materials passing through them. More particularly, it relates to mechanisms which incorporate permanent magnetic rolls for applying the requisite pressure.

Textile drafting mechanisms incorporate spaced apart devices which grip a strand of fibrous material with sufficient firmness to perform the drafting function as the devices operate at increasingly higher speeds. As is well known by those skilled in the art a gripping action by pairs of rolls comprising such devices has usually been achieved by weighting the top roll in each pair, forcing it down upon the bottom roll. Cumbersome weighting equipment comprising weights or springs and associated mechanisms have heretofore been required for this, although it has long been appreciated that the top and bottom rolls or other drafting devices could be forced together by the use of magnetic elements, thereby dispensing with the cumbersome conventional weighting equipment and improving the cleanliness of the operation of the machine.

In magnetic weighting systems the rolls in each pair which operates on the fibrous material are urged together by magnetic forces generated by appropriately poled magnets housed in one or both of the cooperating drafting rolls. In U.S. Patent No. 2,686,940 to V. A. Burnham, for example, a number of particular combinations of magnets in either the top, bottom or both rolls were suggested. As the bottom rolls are generally permanently installed in the machine and are adapted to transmit driving torque, it is considered preferable to form the bottom roll of a continuous solid ferromagnetic material such as steel and incorporate the magnets in the removable top rolls, although with some arrangements the magnetic elements may be incorporated in the bottom roll with advantageous results or even in both top and bottom rolls. In all events the other roll of the pair must be formed of magnetic material, which, of course, includes both ferromagnetic and other magnetic materials.

In current preferred designs of a top roll such as is shown, for example, in U.S. patent application, Serial No. 782,695, filed December 24, 1958, a cylindrical permanent magnet is inserted in the central portion of a nonmagnetic tube and solid ferromagnetic pole pieces are inserted in the tube at each end. Each top roll is placed in horizontal running position resting against a bottom roll and a flux path is thus created via the ferromagnetic pole pieces associated with the top roll, between the pole pieces and the bottom roll, and through the bottom roll. Each bottom roll is adapted to be rotated in fixed bearings and the top roll is rotated through frictional drive by the bottom roll.

The bottom roll may also include permanent magnetic materials therein and may act either in conjunction with a permanent magnetic top roll or not, depending upon the weighting and degree of driving force required, since the upper roll of the pair is frictionally driven by the lower roll. This is especially important with drafting elements of the type having both upper and lower aprons with which this invention is especially concerned, since it for the first time makes possible the driving of an upper apron drafting element by a lower apron driving ele- Patented Mar. 5, 1953 ment Without the employment of apron-damaging knurled or fluted roll portions, although these may be employed for special reasons on either upper or lower rolls if desired.

With all the advantages of magnetic weighting it would be anticipated that magnetic drafting systems would long have been adopted in the textile industry. But adoption has been slow because of a variety of problems. For example, top rolls especially those employing short upper aprons must periodically be removed for cleaning and infrequently for replacement or repair, such as replacement or repair of the cots and aprons in particular. Each of these operations involves removing a top roll, performing the maintenance, and replacing the top roll. However, because of the powerful permanent magnets which must be used and the close spacing of the top is thereby encountered as well as damage to one or both of the rolls caused by the efforts to take them apart; The same thin-g is true, but to a lesser extent when thepermanent magnets are incorporated in the bottom roll,"

since the top rolls are always magnetized to some extent even without permanent magnets.

Additionally, with drafting elements having magnetic top rolls even where a non-permanent magnetic bottom roll is employed and vice versa it is necessary that the rolls be positioned in a specific manner as regards to the north and south poles and not exchanged end for end as even slight variations in the weighting forces affect' the quality of the product produced, but maintenance personnel frequently do not appreciate or pay attention to this fact.

Furthermore, it has been thought that the high degree of fiber control made possible by the use of a double apron drafting element was not feasible in practical' machines because of insufficient magnetic'forces to urge double aprons together and other problems due to magnetic circuitry. Hence, such systems have not been used, and the known control of double apron systems has not heretofore been available with magnetically weigh-ted systems.

Other problems encountered in the textile industry in general include the complexity of frames heretofore known which have limited maintenance and assembly to relatively highly skilled labor, affecting the costs of installation and care.

The present invention relates to these problems and its principal object is to provide an improved magnetically weighted drafting element particularly one of the double apron type capable of utilization by relatively un-' skilled personnel.

A feature of the invention is the ability to adequately drive double apron drafting elements frictionally from the bottom roll without the use of knurled or fluted apron contacting roll portions, thus enhancing apron life to a surprising degree.

Another feature of the invention is the provision of a series of drafting devices adapted to successively work on a sliver passing therethrough, with magnetic top and bottom rolls mounted in a predetermined magnetic relationship so that the top rolls are removable without problems and are easily put back tionship during maintenance.

in their current rela- Another feature is the combination of unitary nonmagnetic roll supports in a drafting frame with magnetized rolls which greatly increases useful magnetic power.

A further feature is the use of a lower apron bar in conjunction with an apron device, as a prime reference for mounting a top magnetized roll.

Other features and advantages of the invention will become apparent as the following description of the preferred embodiment of the invention progresses, in conjunction with the drawings, wherein:

FIG. 1 is a vertical section of a preferred embodiment of the invention taken through a series of drafting devices on a plane generally parallel with the line of travel of a sliver through the series;

FIG. 2 is a partial vertical section illustrating the top front roll support mounted on the lower apron bar and top back roll support mounted on the trumpet bar;

FIG. 3 is a partial vertical section illustrating the middle fiber control device and especially its upper apron roll cage side members mounted on the lower apron bar;

FIG. 4 is a view in partial section of the upper apron roll taken on line 4-4 of FIG. 3, showing the particular construction of that roll in conjunction with its cooperating bottom roll;

FIG. 5 is a top projection of the embodiment on line 5-5 of FIG. 1, parallel with the planes of the rolls, and

FIG. 6 is a front sectional elevation taken on the lines 6-6 of FIG. 5 but showing a modification wherein permanent magnets are incorporated in the bottom roll.

Referring now to the preferred embodiment of the invention of the drawings, on a frame 30 there is mounted front and. back. roll devices. 32 and 34 respectively and a middle fiber control device36, forming a drafting series for drafting a textile sliver. The bottom drafting rolls 38 and 40 of the roll devices may be ferromagnetic bil lets, preferably steel, or may include permanent magnets. In either event they extend the. length of the frame and serve as bottom rolls in a number of like side-by-side drafting series. These rolls are rotatably mounted in bearings fixed in the frame. and driven by means not shown. I

The front top roll 52 is supported against bottom roll 38 by unique unitary support members 56 clearly illustrated in FIG. 2. Each support member comprises av 5.0and 52v aremagnetized, each containing a cylindrical.

permanentmagnet longitudinally aligned therein.

The middle fiber control device 36, best shown in FIG. 3, comprises a bottom. and a top apron assembly. The

bottom apron assembly comprises an endless apron 44.

withinwhich is.v mounted a bottom apron roll 42, either with or. without permanent magnets, but having a smooth apron driving portion 43, a bottom apron bar 46 and an apron tension roll 48. Both the bottom apron roll and the apron bar extend the. length of the frame, serving identical function in side-by-side apron devices in the frame. The bottom apron roll is mounted for rotation and provided with driving means not shown.

The, top apron assembly comprises a short endless apron" 62,. and within, the loop thereof, a top apron roll 69 and a tensor element 64. The top apron and bottom apron are in face-to-face running contact. These aprons must be. urged, together with considerable force and accordingly the top apron roll, is. magnetized, having a particular construction (hereafter described), and related An integral rearward extension 565 is d. to the bottom roll so that no spurious magnetic paths exist but rather all magnetic force available is utilized to urge the aprons together. This relation is achieved as follows: The top roll is supported relative to the bottom roll by two non-magnetic cradle side members 58 spaced apart and held together by the tensor 64 by means of tensor extension 64a, b which fit directly into apertures in the non-magnetic side members forming a cradle. In

the preferred embodiment of the drawings the cradle side mem ers 52; are solid castings of frictionless, rigid plastic which do not create unwanted flux paths. These cradle side members each have a gudgeon receiving half bearing surface 58a. The gudgeons 61 of the top apron roll 60 are placed in these, and the rolls are held in this position by cooperation with the top apron and tensor. This top apron assembly is supported upon the bottom apron bar 46. For this purpose a bottom restraining projection 58b extends integrally from the rearward edge of the each cradle side member 58, adapted to engage a matching slot in the apron bar, restraining forward movement of the top apron assembly during movement of the aprons. The top apron 62 is positioned with respect to the bottom apron by the cooperation of these projections with their matching slots in the apron bar, and also by adjustment screws63 extending between a forward portion of the apron bar and each cradle side member, which screws permit adjustment of the spacing between the tensor and the apron bar.

As noted above, the double apron device utilized in this invention depends for its operation upon the particular construction. of the top apron roll' and its relation to the bottom. apron roll, which promote high magnetic attracting forces because of the desirable flux paths of the structure.

Referring to FIG. 4, the topapron roll includes a cylindrical permanent magnet 14 and novel pole assemblies 15 at each end comprised of ferromagnetic hollow bosses 18 and inserts therein. The bosses 18 are fitted over the ends. of the magnet, and are preferably joined to a non-magnetic sleeve 16 extending between the bosses, around the magnet. At 18a, the boss is of the same diameter as sleeve 16 and so provides a narrow flux gap 19 between pole piece 18 and bottom roll 42, to create as high an attractive force as possible, while at 1812 the bosses are reduced in diameter and preferably are smoothly finished to receive and drive apron 62 without damaging it. Interior of the bosses. and outwards from the magnet there is a highly magnetically permeable iron core 2%, preferably with a hardened gudgeon pin 22 held in a central opening in. the core 20 and protruding therefrom, although a unitary pin could be used. The entire the bottom apron roll 42 and through the bottom apron roll completing the magnetic circuit. Thus virtually all the magnetic force tends to draw the ferromagnetic'bosses down upon the. lower apron roll. The novel pole assembly and the magnet therein promote concentration of magnetic flux between the top and bottom rolls as desired Little magnetic force is lost at the gudgeon region due to the use of the non-magnetic cage side members 58. Bottom apron 44 and top apron 62 are urged thus together with sufficient force to enable them to perform the drafting operation in a wide range of appdcations yet their smooth roll driving portions prevent apron damage. which would otherwise bethe result of utilizing the desirably. high forces. employed.

Referring to FIG. 5, each of the magnetic top. rolls, including the top apron roll, has its left end of matching polarity with left ends of the other magnetized top-rolls in the series, and accordingly the right end of each top roll has matching polarity withthe right ends of the other top rolls in the series. By this particular novel relationship, whenever one of the top rolls in the series is withdrawn from the frame, there is no tendency for this loosened roll to snap towards its neighbor in the series. On the contrary, the roll is repelled by its neighbor and removal and replacement is facilitated. Thus the degree of care necessary is greatly decreased, and relatively unskilled personnel can be employed. If magnetic bottom rolls are also employed, the same effect is achieved by reversing their polarity relatively to the top rolls.

For even greater simplification, visual and mechanical indicators are provided on each magnetized top roll indicating the proper orientation of the roll for replacement in the machine so that the rolls will not be inadvertently exchanged end for end. In the preferred embodiment of the drawings, best shown in FIG. 5, this visual indication is provided in series I therein by making the left hand gudgeons 80 of the rolls and the receiving bearings of a first size and making the right hand gudgeons 82 and bearings of each of the rolls in a second size, visually substantially different from the first size, so that incorrect placement is mechanically impossible.

Furthermore, as also illustrated in FIG. 5, in a preferred embodiment adjacent series of drafting elements are related in the following manner. The polarity of the ends of the rolls of each series in abutting relationship are the same. Thus, as shown in FIG. 5, the right ends of each top roll in series I have a north polarity and the left ends of the top rolls in series II have a north polarity similarly, abutting ends of series I and III have south polarity. If magnetic lower rolls be also employed, then their polarity is reversed with respect to their corresponding top rolls so that adjacent top and bottom roll poles will always be of opposite polarity for maximum attractive force therebetween. With these arrangements, lateral magnetic attraction is avoided, allowing workmen a great latitude of lateral movement of the rolls during maintenance without magnetic interference. To promote interchangeability of the elements, the gudgeon size for the north end of each roll, for all series, is of the same dimensions, and likewise for the south gudgeons.

The operation of this improved textile drafting mechanism should be understood from the above description. A strand of fibrous material is introduced through the trumpet and between the rolls of the rear roll device, then between the aprons of the middle fiber control device and then between the rolls of the front roll device. Magnetic forces alone create the needed pressure upon the fiber strand in each device, and the devices are operated in the conventional manner at increasing speeds, from back to front. Accordingly, the fiber strand is properly drafted in a frame of extremely simple construction, operation, cleaning and repair. Heavy cap bars are gone from the frame, replaced by light-Weight support elements. With the heavy weighting apparatus gone, light duty frictionless bearings are utilized and no fly-collecting lubricating oil need be employed.

A double apron device is preferably utilized with desired pressure between the aprons without heavy weights and without saddles, stirrup and levers. For support of the top apron roll in the double apron device, integral molded plastic cradle side members are adapted to be positioned upon the apron bar. Rearward projections from each of the cradle side members engages the rear portion of the apron bar. These projections perform the essential and unique function of restraining forward movement of the top apron roll and cradle assembly, thus countering the dynamic reaction of the top apron roll in response to the driving movement of the bottom apron assembly and causing the cradle assembly to effectively pivot about the projection, down against the adjusting screws.

To clean the machine, for instance, each top roll and top apron assembly can be individually removed Without even touching any other element. All can be removed and replaced at the same time with no danger of detri- 6. mental interchange by an unskillful or inattentive workman.

In FIG. 6 is shown a modification of the invention wherein a magnetic bottom roll is employed, such roll having a smooth shell 92 which may be of a ferromagnetic material such as steel. Fitting snugly in this tubular shell are several permanent magnets 94, spaced from each other partly by non-magnetic sections 95 and partly, also, by soft iron or soft steel pole pieces 96, one of these latter sections being placed inside each of the smooth apron contacting roll portions 97 directly beneath the upper roll bosses 18. With such a magnetic lower roll, attractive forces are increased when permanently magnetic upper rolls are also used. However, it is contemplated that a ferromagnetic upper roll, without permanent magnets but of the same outer configuration above described may also be used to make easier roll removal for cleaning and the like. With such lower rolls, the like adjacent pole arrangement above described with relation to FIG. 5 is preferably utilized to aid in top roll removal even if nonpermanent magnetic top rolls be employed.

The invention therefore includes a unique magnetic drafting frame including a series of drafting devices. The apparatus of the invention eliminates many parts heretofore essential, and is extremely simple to adjust and maintain with even the most unskilled personnel.

What is claimed is:

1. A magnetic drafting mechanism of the character described including front, middle and rear sets of devices for feeding and controlling a strand of discontinuous fibers, said devices being arranged one in advance of the other in a series to act successively on a strand, the front and rear devices comprising rotatably mounted bottom rolls of magnetically attractable material and overlying top rolls having cylindrical magnetic means therein disposed longitudinally therewith and having pole assemblies of ferromagnetic material with a gudgeon extending from the outward end of each pole assembly, front and rear integral slotted supports comprised of non-magnetic material cooperating with said gudgeon members, rotatably positioning said rolls to rest against matching bottom rolls, and the middle device comprising an endless underlying strand supporting lower apron having within its loop a lower magnetically attractable apron driving roll and a fixed apron bar forward of said apron driving roll, and an endless overlying apron mounted above and contacting said lower apron and having within its loop an overlying apron roll and an apron tensor member forward of said overlying apron roll, said overlying apron roll containing magnetic means therein and having ferromagnetic pole assemblies at each end, each comprising a hollow end boss machined to receive an apron thereon, a highly permeable core fitted therein, and a hardened gudgeon pin held centrally therewith and protruding therefrom, said magnetic means having one pole located within each boss in the zone defined by the portion of the boss adapted to receive an apron thereon, said overlying roll and said tensor member being mounted at their ends on cradle side members of non-magnetic material, said cradle side members providing for engaging said apron bar to restrain forward movement of said overlying middle roll and cradle assembly solely with reference to said apron bar, said lower apron driving roll and said overlying apron roll thus being magnetically drawn together urging the in-between section of the aprons together.

2. The drafting mechanism of claim 1 wherein said magnet means in each of said overlying rolls is so orientated in running relation that the pole of each magnet means in each top roll in the series on the same hand is identical.

3. The drafting mechanism of claim 1 wherein the gudgeons of each roll corresponding to the north pole of the magnet therein contained is of a first size, and the gudgeons of each roll corresponding with the south pole 7 of the magnet therein contained is of a different, second readily visually different size whereby a workman can readily visibly determine the proper orientation of a roll during maintenance.

A textile drafting machine assembly comprising a series of spaced apart magnetized rolls disposed along a sliver path, each roll having opposed end portions of north and south magnetic polarity, a matching second series of other rolls formed of magnetically attractable material, each of said other rolls cooperating with a magnetized roll of the first plurality to comprise a drafting device, means positioning each of said magnetized rolls so that its left end is of matching polarity With the left ends of every magnetized roll in said series, and so that its right end is of matching polarity with the right ends of every magnetized roll in said series and of opposite polarity to that of the left end.

-5. Atextile drafting machine as set forth in c1aim'4, wherein said positioning means includes gudg'eons on each side of said magnetized rolls and complementary bearing surfaces on said machine for supporting said gudgeons, the gudgeons on the left-hand side of said magnetized rolls being of a dilferent size than the gudgeons on the right-hand side of said magnetized rolls.

References Cited in the file of this patent UNITED STATES PATENTS 1,794,578 Broch Mar. 3, 1931 1,897,137 Maynell Feb. 14, 1933 2,329,655 Shaw a Sept. 14, 1943 2,532,275 Whittaker Nov. 28, 1950 2,677,858 Kuehn et a1. V May 1 1, 1954 2,686,940 Burnharn a .a Aug. 24,1954 

4. A TEXTILE DRAFTING MACHINE ASSEMBLY COMPRISING A SERIES OF SPACED APART MAGNETIZED ROLLS DISPOSED ALONG A SLIVER PATH, EACH ROLL HAVING OPPOSED END PORTIONS OF NORTH AND SOUTH MAGNETIC POLARITY, A MATCHING SECOND SERIES OF OTHER ROLLS FORMED OF MAGNETICALLY ATTRACTABLE MATERIAL, EACH OF SAID OTHER ROLLS COOPERATING WITH A MAGNETIZED ROLL OF THE FIRST PLURALITY TO COMPRISE A DRAFTING DEVICE, MEANS POSITIONING EACH OF SAID MAGNETIZED ROLLS SO THAT ITS LEFT END IS OF MATCHING POLARITY WITH THE LEFT ENDS OF EVERY MAGNETIZED ROLL IN SAID SERIES, AND SO THAT ITS RIGHT END IS OF MATCHING POLARITY WITH THE RIGHT ENDS OF EVERY MAGNETIZED ROLL IN SAID SERIES AND OF OPPOSITE POLARITY TO THAT OF THE LEFT END. 